Join Date: Jan 2003
Location: montreal, SA8300HD, Crown CT-400, Alesis RA150, Sony STR-DG500, Tannoy 15"/12"/8"/6", Sony KDL-55EX6
Thanks for the comments.
I have been in contact today with Tannoy Canada and they recommend that I swap the magnet structure between the two drivers to see if the problem moves with the structure.
Removing the structure requires me to first remove the woofer cone in order to expose the bolts hidden under the spider.
If the problem moves with the structure, I can further breakdown the structure into its three components, which are - one forward flux plate glued to the cylindrical-hollow magnet, a rear flux plate, and finally an inner waveguide core.
According to Tannoy, a faulty waveguide or rear flux plate can contribute as much to the problem as a weakened magnet.
These drivers were once in the studios of the C.B.C. (Radio-Canada) here in Montreal and came on the second hand market about 10 years ago. So they surely saw action during their tenure.
Tannoy Canada does not have a magnetizing apparatus, but feels confident that there is still at least one company in the Toronto area capable of remagnetizing.
Once we know which magnet part is responsible, then we will move on to the next step.
By the way, the voice coil resistances of both LF and HF are within 1/10 ohm of the values of the matching driver.